A. Field of the Invention
The device of the present invention generally relates to a spark gap for a high voltage lightning or surge arrester, that is, a lightning or surge arrester for use on power systems of 2400 volts and higher, and, more particularly, to a current limiting spark gap for a high voltage valve type lightning or surge arrester.
B. Description of the Prior Art
Valve type surge arresters having a spark gap electrically connected in series with one or more blocks of non-linear resistance valve material and electrically connected between an electrical power line conductor and ground are well known in the prior art. Many prior art spark gaps utilize magnetic means, such as permanent magnets or electrical coils, for elongating electrical arcs to develop high arc voltages and to facilitate the interruption of power follow current.
Other prior art spark gaps utilize conductive electrode and arc chamber configurations to elongate power follow current arcs without the use of the above-mentioned supplementary magnetic means. Examples of the latter type of spark gaps are illustrated in U.S. Pat. Nos. 2,917,662; 3,242,376; 3,259,780; 3,504,226; and 4,052,639. Illustrative examples of other prior art electrode configurations are set forth in U.S. Pat. Nos. 2,890,389; 2,913,626; 3,361,923; and 3,968,393. Generally, the spark gaps illustrated in most of the above-identified patents suffer from one or more deficiencies. For example, a common deficiency is the necessarily complex and expensive configurations of the spark gaps. In addition, spark gaps in at least some of the above-identified patents do not develop sufficiently high arc voltages to significantly enhance power follow current limitation.
Thus, efforts are continuously being made in this particular art to develop new and improved conductive electrode and arc chamber configurations to increase arc voltages and thereby achieve improved power follow current limitation. Illustrative results of such efforts are set forth in applicant's prior U.S. Pat. No. 4,052,639. The spark gaps disclosed in this application represent further efforts by applicant to develop new and improved conductive electrode and arc chamber configurations for achieving improved power follow current limitation.